HEXUS.bang4buck and HEXUS.bang4watt
Putting all the numbers into perspective, let's take a closer look at overall performance. We've decided to focus on all eight games and compare the two best cards from each company.
In a rough-and-ready assessment of the cards' bang for buck, we've aggregated the 2,560x1,600 frame-rates for eight games, normalised them* and taken account of the cards' prices.
But there are more provisos than we'd care to shake a stick at. We could have chosen eight different games, the cards' prices could have been derived from other sources and pricing tends to fluctuate daily, especially for pre-release GPUs.
Consequently, the table below highlight a metric that should only be used as a yardstick for evaluating comparative performance with price factored in. Other architectural benefits are not covered, obviously.
|Graphics cards||NVIDIA GeForce GTX 580 1,536MB||ASUS GeForce GTX 480 1,536MB||HIS Radeon HD 5970 2,048MB||Sapphire Radeon HD 5870 1,024MB|
|GPU power consumption**||252||244||238||139|
* the normalisation refers to taking playable frame rate into account. Should a card benchmark at over 60 frames per second in any one game, the extra fps count as half. Similarly, should a card benchmark lower, say at 40fps, we deduct half the difference from its average frame rate and the desired 60fps, giving it a HEXUS.bang4buck score of 30 marks. The minimum allowable frame rate is 20fps but that scores zero.
** the GPU power consumption is derived from subtracting a flat rate of 100W - indicating system power-draw without a card - from the Call of Duty: MW2 load figure. While this figure isn't solely indicative of power pulled by the GPU, as the CPU also throttles up, it's a better metric than using peak system-draw alone.
*** the HEXUS.bang4watt score is a crude measurement of how much normalised performance the GPU provides when evaluated against GPU power-draw that's shown in the table: the former is divided by the latter. We're using the peak power-draw numbers obtained by running real-world Call of Duty: MW2.
EvaluationLet's go for the NVIDIA GPU comparison first. GTX 580 provides an average performance boost of 15.1 per cent when compared to GTX 480. Normalise the numbers and that figure rises to 23.4 per cent, because the GTX 580 is able to pull closer to 60fps at the taxing 2,560x1,600 resolution. Factor in the expected £399 price and the new GPU also offers a better bang4buck. This means the extra outlay is more than compensated by increased performance.
But where GTX 580 really gives the '480 a good kicking is with respect to performance per watt, where a lot more speed is gained with minimal power-draw increase. In case we haven't made it abundantly clear, GTX 580 is better than GTX 480 in every way.
Moving across to the red team, Radeon HD 5970 remains the fastest graphics card on the planet, going by our eight games, even with sub-par performance in Civilization V. GTX 580 bridges most of the gap, though, showing just how potent a GPU it is. The Radeon's performance per watt is a little better, as well.
Radeon HD 5870 is still AMD's fastest single-GPU card - yeah, we know what's coming - and it falls comfortably behind both the GTX 580 and 480 GPUs in the performance stakes.